Window construction and glass block for use therein



T. W. GLYNN Dec. 7, 1965 WINDOW CONSTRUCTION AND GLASS BLOCK FOR USE THEREIN 3 Sheets-Sheet l Filed Jan. 8, 1962 .u ,.ZZZAVAVAVAVA;

INVENTOR. Theodore W Glynn HLS` ATTORNEYS T. W. GLYNN Dec. 7, 1965 WINDOW CONSTRUCTION AND GLASS BLOCK FOR USE THEREIN 3 Sheets-Sheet` 2 Filed Jan. 8, 1962 INVENTOR. Theodore W. Glynn BY 10.444; 1li/1.0; M

H/S ATTORNEYS Dec. 7, 1965 T. w. GLYNN 3,221,450

WINDOW CONSTRUCTION AND GLASS BLOCK FOR USE THEREIN Filed Jan. 8, 1962 3 Sheets-Sheet 3 F ig. /3

INVENTOR. Theodore W Glynn BY A, M47 M H/S ATTORNEYS United States Patent 3,221,460 WINDOW CUNSTRUCTION AND GLASS BLQCK FOR USE THEREIN Theodore W. Glynn, Kingsport, Tenn., assigner to Americant-Saint Gobain Corporation, Kingsport, Tenn., a

corporation of Delaware Filed Jan. 8, 1962, Ser. No. 164,715 Claims. (Cl. 52-616) This invention relates to a window construction and glass block for use therein. The invention is described particularly herein in connection with window constructions for fallout shelters, the window construction being such as to effectively stop gamma radiation from fallout, but certain features of the invention are applicable to window constructions used for other purposes.

The designs for family fallout shelters as published by the Oihce of Civil and Defense Mobilization, Bulletin MP-lS, make no provision for windows, presumably because a window thick enough to effectively stop the radiation is not commercially available and if made by the usual methods would be very expensive.

Lighting in the standard designs of fallout shelters is provided by a single battery operated flashlight bulb milliampere) and since the battery will run down or be already dead when required, the need for windows seems obvious. Also, for psychological reasons it seems desirable for the occupants to know the difference between night and day.

I have developed a relatively inexpensive and practical Window construction and glass block for use in fallout shelters. Several types of constructions according to the invention are described herein, certain types admitting light, whereas the other types not only admit light but are such that vision through them is possible.

Briefly described, one embodiment of my invention is directed to a window construction comprising a Wall having an opening extending through it, a glass block inthe opening, the glass block comprising a plurality of glass sheets assembled in side-by-side relation, the glass sheets extending parallel to the light path through the glass block. Such window can of course be also used in the ceiling of an underground shelter. referred to herein, it is intended to include a ceiling. The invention also relates to a glass block comprising a plurality of glass sheets assembled in side-by-side relation, all surfaces of the glass block except the ends being coated with a highly reflective material. It also relates to a solid glass block having all of Yits surfaces except the ends coated with a highly reflective material.

In the accompanying drawings which illustrate several embodiments of my invention:

FIGURE 1 is a vertical section through a portion of a wall showing my window construction for a fallout shelter;

FIGURE 2 is a vertical section taken on the line II-II of- FIGURE 1;

FIGURE 3 is an isometric view of one embodiment of a glass block made according to my invention;

FIGURE 4 is an isometric View of another embodiment of a glass block made according to my invention;

FIGURE 5 is a vertical section taken on the line V-V of FIGURE 4;

FIGURE 6 is a vertical section similar to that shown Where a wall7 isl 3,221,460 Patented Dec. 7, 1965 in FIGURE 5, but showing another embodiment of my invention;

FIGURE 7 is a broken isometric view of another embodiment of my invention;

FIGURE 8 is a vertical section taken on the line VIII-VIII of FIGURE 7; and

FIGURES 9-13 are isometric views of five other embodiments of my invention. In FIGURE 1l for clearness of illustration only, the top glass sheet is shown displaced above the remainder of the block.

According to the Oice of Civil Defense, a total mass of 30() pounds per square foot of wall area is required to effectively stop the gamma radiation from fallout. Since ordinary commercial window glass has a specific gravity of 2.52, this means that the window must be approximately two feet thick. -In one form of my invention, the glass block has square ends 8 x 8" like the end of a standard concrete block. A solid block of glass 8 x 8 x 24 could be made, but the manufacture of such a block is expensive because of the molds required and the long annealing time.

I have invented a laminated block made up of sheet glass which is readily available. Ordinary laminated glass is made with a plastic lm between the glass sheets, the plastic film having the same index of refraction as the glass sheets, and is sealed to the glass sheets by heat and pressure in an autoclave. For a 24" thick window using 1% thick glass sheets, 64 such sheets would be required and special equipment would be required to laminate such a product. In order to avoid these diiculties, I make up the glass block by laminating 2O glass sheets of a size 8 x 24 x which gives me approximately the same size finished block as would be obtained by laminating 64 of the 3s" thick glass sheets in the usual manner. My glass block is installed in the opening in the wall with its ends exposed. Accordingly, the light passes parallel to the glass sheets or edgewise through each sheet rather than passing perpendicularly to the sheets as in ordinary laminated glass.

The layers of adhesive adhering the glass sheets to form a glass block can be very thin (two or three thousandths of an inch) so that in my glass block it makes little difference in total light transmission Whether the adhesive is transparent or not since the adhesive forms less than 1% of the area exposed to the light. If, according to the prior art, a laminated block of glass sheets were arranged in a wall so that the light passed perpendicularly to the planes of the sheets, it would not be possible to use a translucent or an opaque adhesive because suiiicient light would not be transmitted through the glass block. In my glass block, however, translucent or opaque adhesives may be employed, among which may be mentioned pitch, epoxy resin, sodium silicate, or Portland cement. Also, according to my invention, the adhesive can be applied only at the borders of the sheets since it serves only to hold the glass sheets together and stop air or water infiltration. However, the adhesive could not be applied only to the borders of the glass sheets if the light path were perpendicular to the plane of` the sheets, as is the case with ordinary laminated glass windows, because of the reflection losses at the surfaces of the sheets.

When light passes from glass to air or from air to 2 glass, there is a reflection loss of about 4% (normal incidence, ordinary commercial Window glass) of the light that reaches that surface. Thus, the entering surface will transmit 96% of the light and the leaving surface 96% of the light that reaches it or 96% x .96=92.l6% transmission, neglecting the light absorbed in the. glass itself. With 64 sheets and 128 surfaces the transmlssion would then be .96 raised to the v128th power (.96128) which equals .005377 or .54% transmission. Since the glass itself also absorbs part of the light, it is apparent that the total omission of the laminate between the sheets, or the use of the laminate only at the borders of the sheets will result in practically no light transmission with a 24 thick window. On the contrary, according to my invention adhesive between the glass sheets can be omitted entirely or the adhesive can be used only at the borders of the sheets, and, even if the adhesive covers the whole of the sides of the glass sheets, it makes little difference in the transmission of light through the glass block Whether the adhesive is transparent, translucent or opaque. Thus, the index of refraction of the adhesive does not have to equal the index of refraction of the glass sheets.

Referring now more particularly to the accompanying drawings, and for the present to FIGURES 1-3, a glass block 1 made according to my invention is located in an opening 2 extending through a wall 3. The glass block 1 may take various forms, one of which is shown in `FIGURE. 3. A plurality of glass sheets 4 are assembled in side-by-side relation and are held together by steel bands 5 or in any other suitable manner. Each of the glass sheets 4 has the dimensions 8" x 24 x Twenty of these glass sheets are assembled (although FIGURE 3 shows a lesser number), thereby forming a glass block having ends 6 approximately 8 x 8, the block ibeing 24 thick. Sometimes herein thickness is designated length In this embodiment of the invention no adhesive is employed between the glass sheets. The glass block 1 is inserted in the opening 2 as shown in FIGURES 1 and 2, with the ends 6 of the glass block exposed and the glass sheets 4 extending parallel to the light path 7.

It is desirable that a block as described above, assembled without adhesive between the sheets, be waterproofed to prevent the entrance of moisture which might freeze and cause breakage of some of the sheets. This may be done by dipping the block into paran, waxes, resins or rosins to form an envelope of the coating material on all surfaces of the glass block except the ends. This may be done by covering the ends of the block before dipping it into the coating material or by removing the coating material from the ends of the block if the ends have been coated. A

particularly suitable coating material for this purpose is o paran modified by an extender which is a copolymer of ethylene and vinyl acetate. One such extender is sold under the tradename Elvax by Du Pont. A satisfactory proportion for the coating composition is 90%, by Weight, of parain wax and 10% of the extender, but other proportions in this range can be used. Such coating composition has great flexibility, toughness and adhesive properties. It is translucent, transmits little light, is white, and is highly reflective. An unmodified paraflin might also be used but would not be as satisfactory because of its brittleness and lack of satisfactory adhesion to the glass.

Referring now to the embodiment shown in FIGURES 4 and 5, the glass block 1a is formed of glass sheets 4a of dimensions similar to those shown in FIGURE 3, but instead of mechanically holding the assembled sheets together to form the block, sheets S of laminating adhesive are employed between the glass sheets 4a. As shown in FIGURE 5, the laminating adhesive sheets are substantially coextensive with the sides of the glass sheets. The block 1a is inserted into the opening in the wall wit-h the ends 6a of the glass block exposed.

The embodiment shown in FIGURE 6 differs from that shown in FIGURE 5 only in that in FIGURE 6 the laminating adhesive 8a located between the glass sheets 4b 4 is applied to the glass sheets only at the borders of the glass sheets.

Referring now to the embodiment shown in FIGURES 7 and 8, a glass block 1c is formed by assembling a plurality of glass sheets 4c, employing an adhesive 8c applied only to the borders of the glass sheets. Sheets of metal foil 9, for example aluminum foil, or other foil having good light reflective surfaces, are interposed between the glass sheets 4c. Instead of employing the metal foils 9, one may metallize both sides of each of the glass sheets 4c with aluminum or the sheets can be silvered like a mirror. The use of the metal foils 9 or the silvering or metallizing of the sides of the glass sheets, increases the total light transmitted through the glass block. Even though the light path is parallel to the individual sheets in the embodiments shown in FIGURES 3 and 4, there is a loss of light from the sides of each sheet by diffusion. By employing the foil 9 as shown in FIGURE 8, part of the light which escapes and is lost from the sides of the sheets is reliected back into the glass, resulting in a substantial gain in the total light transmitted.

Metallizing or silvering of the surfaces of the glass sheets is more effective than the use of aluminum foil between the sheets Ibecause reflection losses when the light passes from glass to air to aluminum foil to air and back into the glass are eliminated.

The amount of light transmitted through the blocks can be increased in several Ways irrespective of the particular Imanner in which the glass blocks are formed. For instance, the amount of light transmitted through the block 1 of FIGURE 3, or through the block 1a of FIGURE 4, or through the block 1c of FIGURE 7, can be increased Iby grinding and polishing the ends of each individual glass sheet before assembling the sheets into the block, or by grinding and polishing the ends of the finished glass block.

The application of a non-reflective coating such as is used on camera lenses, to the ends of the block whether ground and polished or not, will also improve the light transmission. A coating of magnesium uoride applied in a thickness of approximately one quarter the wave length of yellow light is an example of a non-reilective coating.

Another means of increasing the light transmission through the glass block is illustrated in FIGURE 9. A glass block 1d which may be similar to any of the glass blocks shown in FIGURES 3 through 8, is made by assembling glass sheets 4d by means of adhesive 8d, the ends of the glass sheets having regular cut edges instead of being ground and polished. Of course, the ends of the glass sheets 4d may be ground and polished, but this is unnecessary. A glass panel 10 is then laminated to each end of the glass block, the panels 10 being made of clear glass (Window or plate glass) using a transparent ad-hesive 11 having a refractive index approximately the same as the glass. Various transparent adhesives of this character are available on the market, one being sold 4under the tradename Glasshesive by Adhesive Engineering Company, this being an epoxy resin, another being sold under the trandename Sunweld EC 2019" by Minnesota Mining and Manufacturing Company, this being a synthetic resin. Both of these adhesives are viscous liquids before setting and will conform to the rough ends of the glass block at the interface. A non-reflective coating on the outside of the glass panel 10 will also improve the light transmittance of the block.

The total transmission of an 8 X 8 x 24" glass block made according to my invention cannot be measured by standard equipment because the block is too large. Also, the standard method would not give a true picture because the light source is a projector lamp with practically parallel rays which would not be the case in the shelter (unless the rising sun were normal to the face of the window). I have, therefore, used `another method as follows: A square cardboard tube 24 long and 8 in diameter was installed in a Wall `and a foot-candle meter reading was made at the inside end. A glass block 8" X 8" x 24 made with 20 sheets of /s x 8 x 24 crystal was mounted in the wall below the cardboard tube and llight readings Vwere made at the inside face of the wall. The reading at the inner end of the cardboard tube read 40 foot-candles ahd the reading .at the inside surface of the "glass block was 180. Thus, the glass window made acicording t`o the present invention admitted 41/2 times as I nuch light as a standard window or a hole of the same size through a 24 thick wall. If a glass block as shown in FIGURE 8 is used, the glass block having aluminum foil between the glass sheets, the reading at the inside surface of the wall increases to 270 foot-candles, or a gain of 675%. The reason for this is that the hole in a 24 wall admits only light rays which are almost parallel to the longitudinal :axis of the hole and since the hole was only six feet above the ground, it received little light from the sky at the horizon because of the topography. On the other hand, the exposed end of the glass block window according to the invention admitted light from a wide area of the sky as defined by a horizontal arc of .about 114 and a vertical arc of 57.

Thus far in the `description of the invention I have referred to a wall 24 thick and glass blocks 24" long placed in the holes in the walls. Other types of aboveground shelters are made using double walls with rock or earth fill in between, and an overall thickness of 36". Under-ground shelters call for three feet of earth overhead with a sheet metal ceiling, a 6l concrete slab with 20 of earth, or 28 of earth over a ceiling made with 3" x 10 wood joists and a wood deck. A 24 thick window recessed into one or both sides of a 36 thick wall or ceiling would not admit nearly as much light as it would in a 24 wall. This is for the same reason that the cardboard tube previously referred to is not as etective as the glass block construction, as previously explained. To correct this condition, either the glass block must be as thick as the wall, or, if a thinner block is used, the recesses in the wall at the ends of the glass blocks should be lined with a highly reective material that will not tarnish. Another means of accomplishing this result is to combine a hood with the glass block, the hood having a length equal to the length of the hole in the wall, the length of the glass block being less than the length of the hood. Such an arrangement is shown in FIGURE l wherein all four sides of the block 1e are enveloped in or surrounded by `a glass hood designated generally by the reference numeral 12. The hood comprises a top glass sheet 13, a bottom glass sheet 14, and two glass side sheets 15. These sheets 13-15 extend beyond the ends of the block 1e, thereby resulting in a recess 16 between the hood 12 and each end of the block 1e. The walls of the recess 16 :are lined with highly reflective material such as aluminum foil or the walls of the recess are metallized with highly reflective material. Instead of lining only the recesses 16 with highly reflective material, the reflective material may cover the entire sides of the glass sheets 13.-15.

Another means of making a glass block having :an overall length or thickness greater than the length of the individual glass sheets employed, involves staggering the glass sheets. Such a block is shown in FIGURE 1l. The glass block designated generally by the reference numeral 1f comprises a series of glass sheets 4f :alternating with a series of glass sheets 4g. The glass sheets are bonded by adhesive 8f. The sheets 4f and 4g are staggered so that they overlap and each of the sheets 4f and 4g has a -length of 30". They overlap for a distance of 24". The total length of the block is 36". The glass block has a top glass sheet 17, a bottom glass sheet 18 and two side glass sheets 19, each of which is 36 long. The staggered relationship of the glass sheets 4f and 4g results in a series of slots 20 and the walls of these slots are provided with metallized, highly reective surfaces.

In FIGURE 12 there is shown a solid glass block 5 designated generally by reference numeral 1g, all of the surfaces except the ends 6g being metallized with a highly reflective metal as indicated by reference numeral 21.

As shown in FIGURE 13, the glass block designated generally by reference numeral 1h is relatively thin as compared with the blocks previously described. All of its surfaces except the ends 6h are metallized with a highly reflective metal as indicated by reference numeral 22. Thin blocks of the kind shown in FIGURE 13 can be placed in the vertical joints between the concrete blocks of a wall. Twenty blocks of the kind shown in FIGURE 13 placed in the vertical joints of the wall would equal the light transmission of a block such as shown in FIG- URES 7 and 8 and consisting of twenty glass sheets assembled with both walls of each of the glass sheets metallized, but better light distribution would be achieved by the blocks shown in FIGURE 13.

In general any kind of glass can be used in making my glass blocks, the preferred glasses being those which are almost colorless and have a high light transmittance. Traces of iron in ordinary window or plate glass give it a noticeable greenish color in thick sections and cause a reduction in light transmitted. The so-called water white lime glasses with an iron content of .04% or less are commercialy available, are relatively inexpensive and are preferred. Special glasses with high transmissions such as optical, high lead or borosilicate glasses can, of course, be used but are more costly and not essential for the practice of the invention.

The invention is not limited to the preferred embodiments, but may be otherwise embodied or practiced within the scope of the following claims.

I claim:

1. A window construction comprising a wall having an opening extending through it, a glass block in the opening, said glass block comprising a plurality of glass sheets assembled in side-by-side relation, said glass sheets extending parallel to the light path through said glass block, said glass block having a glass panel adhered to each end thereof by a transparent adhesive having an index of refraction approximately the same as that of the glass.

2. A window construction comprising a wall having an opening extending through it, a glass block in the opening, said glass block comprising a plurality of glass sheets assembled in side-by-side relation, said glass sheets extending parallel to the light path through said glass block, said glass block having a glass panel adhered to each end thereof by a transparent adhesive having an index of refraction approximately the same as that of the glass, the outside surfaces of said adhered panels being provided with a non-reilective coating.

3. A window construction comprising a Wall having an opening extending through it, a glass block in the opening, said glass block comprising a plurality of glass sheets assembled in side-by-side relation, said glass sheets extending parallel to the light path through said glass block, the length of said glass block being less than the length of the opening in the wall, thereby resulting in a recess in the wall at at least one end of said glass block, the walls of the recesses having highly rellective surfaces.

4. A window construction comprising a wall having an opening extending through it, a glass block in the opening, said glass block comprising a plurality of glass sheets assembled in side-by-side relation, said glass sheet extending parallel to the light path through said glass block, the length of said glass block being less than the length of the opening in the wall, a glass hood integral with said glass block and extending beyond at least one end of said glass block, the length of said glass hood being substantially equal to the length of the opening in the wall, thereby resulting in a recess in said hood at at least one end of said glass block, the walls of the recesses having highly reflective surfaces.

5. A window construction comprising a wall having an opening extending through it, a glass block in the opening,

said glass block comprising a plurality of glass sheets assembled in side-byside relation, said glass sheets extending parallel to the light path through said glass block, said glass sheets being staggered, thereby providing a series of slots at at least one end of the block, the Walls of the slots having highly reflective surfaces.

References Cited by the Applicant UNITED STATES PATENTS Dimmick 117--124 Hansell 117-124 X Keck 20-40 Mathes et al. Fitzgerald.

OBrien 88-1 Friend 50-265 X Speller et al 88-1 McIlvane.

FOREIGN PATENTS France. Great Britain.

HARRISON R. MOSELEY, Primary Examiner. 

1. A WINDOW CONSTRUCTION COMPRISING A WALL HAVING AN OPENING EXTENDING THROUGH IT, A GLASS BLOCK IN THE OPENING, SAID GLASS BLOCK COMPRISING A PLURALITY OF GLASS SHEETS ASSEMBLED IN SIDE-BY-SIDE RELATION, SAID GLASS SHEETS EXTENDING PARALLEL TO THE LIGHT PATH THROUGH SAID GLASS BLOCK, SAID 